Well we also don't know if Clark was referring to letting the boy (we assume?) die.

In Smallville, they showed the Kents willing to go through extremes to protect their son. Even at the end of season 1 he chases the reporter into the storm to stop him and had a pretty hard rage in him that most likely would have gone to the point of killing. Could be a similar case here where someone with less than noble intentions is the topic of discussion.